Friday, August 25, 2006

poor pluto

the new york times reports on pluto's loss of status as a planet. does this set a dangerous precedent? for example, might qpr be in danger of losing its status as a football team?

"Editorial - And Now There Are Eight

Published: August 25, 2006

The world’s astronomers came to their senses yesterday and approved a new definition of the word “planet” that would drop tiny Pluto from the club and relegate it instead to a lesser realm of “dwarf planets.” It was a welcome step away from a proposal that would have kept Pluto as a planet but simultaneously opened the door for dozens of small, icy bodies on the fringes of the solar system.

The crucial vote came after tumultuous debate at a meeting of the International Astronomical Union, which had been considering a proposal to define a planet as any object that orbits a star and is large enough for its own gravity to pull it into a spherical shape.

That definition was scientifically precise but led to results that offended common sense. An asteroid, a small moon, and another icy ball like Pluto would suddenly have been catapulted to planet-hood, swelling the number of planets to 12, with hordes more icy rocks likely to qualify as more was learned about them.

Fortunately, the astronomers have now added another requirement to the definition. Planets must not only be large enough to be round, they must also have cleared out the neighborhood around their orbits. Pluto would not qualify — it orbits in a belt of icy debris on the edge of the solar system. Neither would an icy rock nicknamed Xena, which orbits in that same zone, nor Ceres, a big asteroid that marches in the company of other asteroids. Pluto’s moon, Charon, which had qualified under the first proposal, is also out of the running.

Pluto, with its small size and oddball orbit, should never have been deemed a planet in the first place. Henceforth there will be eight planets, at least three dwarf planets, and tens of thousands of “smaller solar system bodies,” like comets and asteroids. Our only regret is that the astronomers chose the name “dwarf planets” for Pluto’s new category instead of abandoning the word entirely when discussing these less-than-planetary bodies."